Process of paste extrusion

ABSTRACT

Pipes with walls thicker than 4 mm are made by paste extrusion of PTFE powder in the presence of a lubricant. The extrusion is carried out at a reduction ratio below 20:1. The PTFE powder is a mixture of 80 to 99% by weight of coagulated dispersion grade PTFE and 20 to 1% by weight of PTFE having a median particle size less than 50 micrometers. The mixture is preferably a co-coagulation of the two forms of PTFE.



